| Project/Area Number |
63850073
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
電子機器工学
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| Research Institution | Tohoku University |
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Principal Investigator |
NAKAMURA Kiyoshi Tohoku University, Faculty of Eng., Professor, 工学部, 教授 (00005365)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Sadayuki NEC Corporation, Material Development Center, Senior Researcher, 材料開発試作センター, 主管研究員
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1989: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1988: ¥3,400,000 (Direct Cost: ¥3,400,000)
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| Keywords | Actuator / Piezoelectricity / Lithium Niobate / Ferroelectricity / Domain Reversal / Bending Vibrator / Positioner / 強誘電体 / アクチュエータ / ポジショナー |
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| Research Abstract |
Piezoelectric ceramic actuators are not suitable for precise position control, because they exhibit hysteresis and creep. The purpose of this research project is to develop hysteresis-free high-precision piezoelectric actuators using LiNbO_3 crystals with a very high Curie temperature of 1160ﾟC. The results obtained in this project can be summarized as follows: 1. The piezoelectric constants have been calculated for various orientations of LiNbO_3 and the optimum cuts have been searched. The 140ﾟ rotated Y-cut plate has a maximum transverse piezoelectric strain constant d_<23> of 30.3 pC/N and a very high coupling factor k23 of 0.51. The 28ﾟ rotated Y-bar has a maximum longitudinal piezoelectric strain constant d_<22> of 39.6 pC/N and a coupling factor k_<22> of 0.6.2. A LiNbO_3 plate with a ferroelectric inversion layer formed by heat treatment just below the Curie temperature can serve as a bending actuator The dependence of the inversion layer thickness on the heat treatment conditions has been studied. It has been shown that a sufficiently long heat treatment causes an inversion layer as thick as one-half of the plate thickness. 3. The bending actuators fabricated using 140ﾟ rotated Y-cuts have been demonstrated to exhibit excellent linearity, no hysteresis, and no creep. 4. Various fabrication methods for Multi-layer longitudinal-mode actuators have been studied. It proves that even actuators fabricated by lamination using adhesives have no hysteresis, little creep, and excellent linearity with no definite saturation for both positive and negative high voltages. 5. The temperature dependence of the piezoelectric strain constant has been examined. It has been demonstrated that the variation of d_<23> is much smaller than that of ceramic actuators and the actuators can operate over a very wide temperature range.
In conclusion, the LiNbO_3 actuators developed in this research are most suitable for applications requiring precise position control.
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